1. Field of the Invention
The present invention relates generally to the field of markers on wheels for marking surfaces. More particularly, it is a tandem wheel marker for marking horizontal surfaces on building construction members such as beams to indicate positioning of vertical members such as studs and other related construction members.
2. Description of the Prior Art
A marker on a wheel to mark surfaces on which the wheel is rotated is one of the older arts of civilization. There have been a wide variety throughout history. Nearly all have been single wheel types with one or more markers placed on one wheel to mark a surface with each revolution. None have had a tandem wheel construction with an upright handle, a rotation equalizer, a positioning fork, roller guides and other features that make this invention uniquely advantageous for layout marking of buildings under construction. One tandem marker was designed for marking walls aesthetically. But it did not have the measuring, positioning, guiding and handling features of this invention.
Examples of different wheel type devices that have been designed to accomplish various marking objectives include the following U.S. patent documents.
______________________________________ U.S. Pat. No. DATE NAME ______________________________________ 4,372,049 Feb. 8, 1983 Hogue 3,988,835 Nov. 2, 1976 Thornton 1,705,415 Mar. 12, 1929 Melliger ______________________________________
The Hogue patent taught a marker wheel with an optional side wheel with a smaller diameter on an offset axle. One wheel rotated on a surface for positioning one type of upright and the other wheel marked positions for other uprights. This device demonstrates side-by-side in contrast to tandem arrangement of marking wheels employed in this invention. The Thornton device had a single marker wheel attached to a handle and an edge guide to hold the wheel next to an edge of a workpiece while rolling the wheel along with the handle to mark the workpiece. Variations of the Thornton device have been most prevalent in the prior art. The Melliger patent taught a wall printer with at least three printing rollers for putting designs on walls to imitate wallpaper. It did not have a measuring fork, a handle frame for positioning marks on horizontal construction members nor other features that would make it suitable for marking construction surfaces. Neither of the single wheel, side-by-side wheel or tandem wheel devices known previously have provided sufficiently accurate measuring capacity to be suitable for construction marking.